Two-stroke-cycle gas-motor engine.



No. 675,796. Patented Juno 4', I90l. l-l. SCI-IUMM & M. MUNZELL.

TWO-STROKE CYCLE GAS IUTOB ENGINE.

(Application filed m. 11, 1899.) (No Model.) 2 Shah-Shoot I.

No. 675,796. Patented lune 4, l90l.

' H. SCHUMM & M. MUNZELL.

TWO-STROKE CYCLE GAS MOTOR ENGINE.

(Appfication filed Dec. 11, 1899.1 (No Model.) 2 Sheets-Sheet 2.

f'zyj.

UNITED STATES PATENT OF ICE. p

HERMANN SCHUMM, OF BONN, AND MAX MUNZEL, OF MU'LHEIM, GER-" MANY, ASSIGNORS TO THE OTTO GAS ENGINE WORKS, OF

PHIA, PENNSYLVAN IA.

PHILADEL TWO-STRQKE-CYCLE GAS-MOTOR ENGINE;

SPECIFICATION forming part Of Letters Patent No. 675,796, dated June 4, 1 9 O1.

Application filed December 11, 1899. erial No. 739,944. (No model-i To all whom it may concern:

Be it known that we, HERMANN SCHUMM, residing at 85 Coblenzerstrasse, Bonn, and MAX MI'iNZEL, residing at Deutzerstrasse, Mulheim, in the Province of the Rhine, Germany, citizens of Germany, have invented a certain new and useful Improved Method of .cles, whereby an absolutely reliable igirit-iou is insured, while the heat generated by the combustion is utilized to the greatest possible extent.

According to this invention there is forced through the engine-cylinder (which has no compressiomspace) shortly before the piston reaches the inner dead-center a scavenger charge of air, which carries with it theremaining combustion-gases and any particles of still-burning gas mixture and discharges the same through the discharge-valve. 0n the piston arriving at, the dead-center the discharge-valve and scavenger-air valve are closed and a previously-formed homogeneous mixture of gas and air is introduced into the cylinder through a charging-valve while the piston is performing a certain portion of its outstroke, after which, the charging-valve being closed, the charge is ignited and the expansive action due to the heat generated causes the piston to complete its outstroke in doing work. By constructingan engine to obtainthereis'ults set forth in the foregoing paragraph some of the objectionable features heretofore existing in two-stroke-cycle gas motor engiues are overcome, for the reason that the premature ignition of the'c'harges' is avoided,

which frequently occurs with the known arrangements, owing to the entering combustion residues of the previous charge. count ,of this premature ignition it was, gen-- tiblecharge becoming fired by residual burning gas particles or by highly-heated combus- On acerally speaking, not practicallypossible to work two-stroke motors by means of previously-formed homogeneous explosive 'mixtures, as the store thereof contained in the reservoir would be liable to be exploded by SLCh premature ignitions. the mixture-namely, the air and gas-had therefore to be stored separately in different reservoirs or in the same reservoir without being mixed before entering the cylinder, and owing to the shortness of the charging period they had not time to mix thoroughly, so as to insure a reliable ignition and rapid combustion. The present improved construction of gas motor engine effectually avoids the liability to premature ignition by causing the combustion residues and particles of burning gas to be swept out of the cylinder by a scavenger charge of air, enabling explosive charges to be used'of a perfectly homogeneous nature previously formed outside the cylinder. On the other hand, in the case of those two-stroke gas -"m-otors in which a scavenger charge of 'air'has already beenused for clearing out a compressionspace existing in the cylinder behind :the piston when at the end of instroke differes sentially from the present improved method, both as to the manner of formingthe charges and as to the volume of 'th'efs'cav enger charge of air required. 'Wifhthesemotor-engines the ignitio'n of' the 'charg e'sis effected when the piston. arrivesat tlreinner dead-center, so that the introductiouof; the charges m nst necessarily be effected already during the compression period. quently not only the'compressionspace, but

also a considerable portion ofthes'pacepassed' through by the piston'," requires to-be filled with clearingair or air for. combustion into which the as then ehters,*and therefore the mixingof he gas and air constituting a conr bustible'charge'can only take place inthe cylinderdtself, while, as already.stated,"ac* cording to the present invention the charge enters the cylinder alreadyin an intimately- The two parts of engine.

65 rectly after closing the charging-valve.

'5 erable quantity of air is necessary for the scavenger char e, as this has to-force outa large volume 0 cqmbnstion-gases contained in the compression-space and a large portion of the cylinder. The scavenger charge remaining in the cylinder no doubt serves as the air-supply forthe-next explosive charge, but owing to the unavoidable mixture of the scavenger charge with the combustiongases :1. very large yplume of air mustbe' em- I 5 ployed in excess or that required for the explosive charge it all the combustion-gases are to be expelled. According to the present in vention, on the other hand, only a comparartively small quantity of air is required for the scavenger charge-namely, only slightly more than the volume represented by the small dead-space or clearance between pis 'ton and cylinder endso thata saving is effected bothas to work done and weight of Lastly, by the improved construetion of engine hereinafter referred to a very energetic cooling and-clearing of the pist'ous surface is efiected, as the scavenger chagge has to. force its way-at a high speed through the very narrow clearance or dead-space beof thejcompression-space and part of cylinder, in which itconsequent-ly only travels at a slow speed and with imperfect contact for cooling purposes;

On the accompanying drawings, Figure 1 0.. shows an indicator-diagram of the working of the engine, and Fig. 1 shows indicator-dia- 'grams' for variable'amonnts otwork. Figs. 2\ and 3 show, respectively, a diagrammatic longitudinal section and end view of a gas-motor 5 engine according to the present invention.

Figs. 4, 4, 5, and 5 show detached details. A is the engine-cylinder; B, the piston; C, the discharge-valve; d,the admission or charging valve for the explosive charge; e, the valvefor the scavenger-air charge; R, the reservoir for the compressed explosivemixture, and R the reservoir for the compressed clearing air. Toward the end of the discharging period (point I-of diagram Fig. 1) the air-valve 5 5' e is opened and the compressed air entering from the reservoir R drives the remaining combustion products out through the open discharge-valve 0. both the said valves are closed. 0n the other hand, the charging-valve d is opened and admits compressed explosive mixture into the cylinder during the first part of the pistons outstroke, (III to IV of diagram,) which charge is ignited directly at the point IV-that is r ll1i- At the dead-center (II) the engine-sh aft and having cam-disks g g 'g,

which eiiect the openingof the valves through rollers and levers h h" h". .The valve-gear may, however, be arranged in any other suitable known way for etlfecting the above-described operations.

The regulation of the gas-motorengine is eifected by varying the duration of the admis sion oi explosive mixture, and consequently the volume oi. eachexplosive charge. Fig. 1

'shows a series of indicator-diagrams varied in this manner for producing variable amounts of work. \Vi'th this arrangement the ignition of the charges must be made dependent upon the working of the charging-valve in such manner that the ignition in every case occurs immediately after the closing. of the valve. Figs. 4 and 4 and 5 and 5 show two difierent arrangements for this purpose. In the arrangement at Fig. '4 there is combined with the stem of the charging-valve d, through iihe me dinm of a blade-spring 7a, a body 't, which is ordinarily held by a stop It in a definite po i 'tion relatively to the valve-stem,.in which position a contact-piece I, carried by the body '5 and connected to one part of an electric circuit, is kept out of contact with the fixed contact-piece'l, connected to the other part of the circuit.

The lever hot the charging-valve is actuated by means of a movable cam m n, with inclined followingface m, as shown in side view at Fig. 4, and controlled by a governor in the known manner. When the chargingvalve after being held open by lever h-for a length of time determined by the position of cam m n is closed by the action of its spring 10, the body 11 in moving with the valve-spindle continues to move to the left hand by reason of the impetus imparted to it after the valve has closed, and thereby causes contact to be made between 1 and I, thus closing the electric circuit, in which is includedthe igniting device, and effecting the ignition of the charge in the cylinder by an electric spark in the well-known manner.

In the arrangement at Fig. 5 the cam mm for actuating the charging-valve has joined to it a lower long cainn 0, which extends almost completely around the cam-boss, leaving only a small portion, of the latter free. With the lever h of the charging-valve is connected an electrical contact H, which is only closed when the roller of the lever moves over the free part at o of the boss, the circuit being open as long as the roller runs over the cams o n ormn. Consequently immediately after the roller has run of! the inclined fol lowing side m of the charging-cam mn the pressure in the cylinder then suddenly rises lever h causes the contacts I l to close the electric circuit and etfect the firing of the charge, the circuit being broken again as soon as the roller passes onto the cam 0 n.

\Vith the motor-engine can be combined any suitable known arrangement of force-v pump for forcing the gas-and-air mixture or a separate gas-and air pump for producing and compressing the mixture of gas and air, or the said compressed gaseous mixture can be produced independently of the motor-engine. The only essential ifeatnre in this respect is the interpolation ota reservoir R for compressed gas-and-air mixture between the engine-cylinder and the force-pump in order to enable a thoroughly homogeneous mixture of the gas and air to be effected before entering the cylinder. The said homogeneous mixture may contain, in addition to combustible gasand air, any other suitable gas of a neutral or inert nature.

The compressed store of clearing-air in the reservoir R" will require to be replenished either continuously during the working or from time to time by means of a special airpump driven by the engine or separately therefrom. If, as above stated, there be pro vided separate pumps for supplying the compressed airand compressed gases required for the explosive mixture stored in R, the air force-pump for this purpose may be made of such a capacity as to supply not only the air required for the combustible mixture, but also that for the scavenger charges, in which case a special pump for the latter would b dispensed with.

It will be evident that the special reservoir R for the clearing-air and the charging-pin m p therefor might be dispensed with and the necinder of said engine just before the piston reaches the inner dead-center, means for operating a charging-valve for introducing a charge of previously intimately-mixed gas and air to the cylinder during a portion of the outstroke of the piston, and means for firingsaid charge when said valve is closed.

2. In a two-stroke-cycle gas-motor having no com pression-space in the cylinder, means for forcing a scavenger charge of air into the space intervening between the piston and cylinder just before the piston reaches the inner dead-center, means for opening an admissionvalve for the explosive mixture when the piston is home, means for closing said valve at various points of the stroke of the piston, and means for igniting the explosive charge at various points of the stroke of the piston when said admission-valve is closed.

3. In a two-stroke-ovcle gas-motor having no com pression-space 1n the cylinder, means for blowing out the products of combustion when the piston is all but home, an admissionvalve for the explosive mixture, means for opening said valve when the piston is home,

means for closing said valve at various points of the stroke of the piston, and means for ig niting an explosive charge at various points of the stroke of the piston.

4. In a tWo-stroke-cycle gas-motor having no compression-space in the cylinder, an exhaust-valve, operating means therefor, means for blowing out the products of combustion when said valve is opened when the piston is all but home, an admission-valve, means for opening said valve when the piston is at home,'means for closing said valve at various points of the stroke of the piston, and means for igniting an explosive charge at various points of the stroke of the piston.

In testimony whereof we have hereunto set our hands in presence of two subscribing witnesses.

HERMA IN, SOHUMM. MAX MUNZEL,

Witnesses:

WILLIAM H. MADDEN, GEORG LEHMANN. 

